1. Field of the Invention
This invention relates generally to support devices, and, more specifically, to a wall hanger type support device which can be used to support a load from a surface of a wall.
2. Description of the Prior Art
In the past, it has often been desired to hang various articles from the walls of a structure. Typical examples of such articles included works of art, clocks and mirrors. Walls have often been fabricated from materials in which the allowable unit stress was relatively low. Examples include: gypsum board or drywall; plaster applied over lath; etc. Support from such walls was commonly provided by simply driving a nail into the wall. The load was then directly suspended from the nail. However, a substantial problem was presented in that the low allowable unit stress limited the load which could be suspended without having the wall yield locally under the load transferred by the nail. A need existed for a wall hanger which could support a substantial load without causing a failure of the wall surface material and a without resulting in a pull-out of the hanger.
Other devices such as toggle bolts were also developed to support a load from a wall. However, toggle bolts required that a hole be pre-drilled to permit insertion of the toggle and a portion of the bolt through the wall. Toggle bolts also typically required a substantial clearance behind the intended mounting location, to permit the mounting screw to fully engage the toggle against the wall. Additionally, the normal overlength of the bolt of the toggle bolt assembly dictated that substantial time be expended to fully assemble the device by screwing the parts together. Furthermore, the toggle was typically of such limited span that substantial stress concentrations commonly occurred when the toggle contacted the wall, causing an altogether too frequent pull-out of the assembly from the wall. A need continued to exist for a device to suspend a load from a wall, which device did not require a pre-drilled hole for installation, did not require an extensive clearance behind the wall to permit installation, did not require time consuming hand-threading for installation, and which also distributed the applied load over a substantial portion of the wall to reduce unit stresses in the wall.
Typically, an unobscured wall attachment apparatus has remained a visual impairment on a wall. A need existed for a wall attachment apparatus which was not visually obvious.